In my current career I've been very lucky in terms of capital ships.
In early 1940 I came across the Nelson and a Revenge Class Battleship north of Scapa Flow in my VIIC. Sunk the Nelson, the Revenge Class Battleship and two destroyer escorts and got away.
In early 1944 near the entrance to Gibraltar I came across a Bogue Escort Carrier and five destroyer escorts - sunk them all thanks to the Falke / Zaunkonig I torpedoes (they make life so simple!).
A few months later, off the coast of Ireland I encountered a lone passenger vessel at night steaming at 29 knots through the waves. I wasn't sure if this was a legitimate target but it was armed so I figured what the heck, sink it. Three torpedoes sent her to the bottom. Then in the same mission I encountered another Bogue Escort Carrier and four destroyer escorts north of Scapa Flow. Managed to sink the carrier and two of the escorts and got away.
I've been very lucky so far.